1st let me tip my hat to Colorado’s legislature in allowing marijuana / cannabis to be legally sold, as it should of been to anyone who wanted to learn first hand it is not dangerous as our trusting government wanted you to believe. Colorado has it’s right and I personally am impressed that finally a state stood up for it’s citizens rights to choose what they put into their bodies, be it for medicinal or recreational.
I also noticed from media coverage there was a short supply, although there was plenty of warning, the demand was more than anyone anticipated. That being said, it’s time t5o look at some of the impacts this will create.
One, supply is behind demand, this makes it easier to control prices and limits the amount available, as shown on Colorado’s opening day.
Two, the demand on electric from the use of 1000 watt H.P.S. or Medal Halogen lighting is nothing short of a demand on utilities, this demand will be passed on to the consumer as everything else is. Not to mention the electrical cost to vent and cool these rooms down, again an added cost to be passed on to the purchaser of their product.
As a small grower for personal medication I found using these type of lights did not allow me to feasibly grow, in fact I was just below what it cost from the shops. My electric bill usually ran around $350.00 per month. What I found that decreased my costs and still allowed me to get the full spectrum available were Inda-Gro’s induction lighting products. Using a P.A.R. 420 in fact cut my electric bill in half. For one. it uses less electric (420 watts) vs 1000. Ventilation costs removed due to low heat output from these induction bub’s, All that is needed is a oscillating fan for plant movement, not to mention the carbon footprints are reduced greatly, making Inda-Gro environmentally safe, personally my opinion the safest available.
Another major fact these bulbs last for 100.000 hrs without having to change bulbs, at $100.00 per bulb with changing every six months alone could purchase one of these Inda-Gro lights!
Measuring Plant Lighting
An essential piece of information about any molecular species is how much of it is present. Quantitative measures of concentration are one of the cornerstones of biological science. Of all the methods that have been devised for measuring concentration, by far the most widely applied is absorption spectrophotometry. In this technique, the amount of light that a sample absorbs at a particular wavelength is measured and used to determine the concentration of the sample by comparison with appropriate standards or reference data. The most useful measure of light absorption is the absorbance (A), also commonly called the optical density (OD) (Web Figure 7.1.A). The absorbance is defined asA = log I0 / I where I0 is the intensity of light that is incident on the sample and I is the intensity of light that is transmitted by the sample.
The absorbance of a sample can be related to the concentration of the absorbing species through Beer’s law:
where c is concentration, usually measured in moles per liter; l is the length of the light path, usually 1 cm; and ε is a proportionality constant known as the molar extinction coefficient, with the units of liters per mole per centimeter. The value of ε is a function of both the particular compound being measured and the wavelength. Chlorophylls typically have an ε value of about 100,000 L mol–1 cm–1. When more than one component of a complex mixture absorbs at a given wavelength, the absorbances due to the individual components are generally additive.
The absorbance is measured by an instrument called a spectrophotometer (Web Figure 7.1.B). The essential parts of a spectrophotometer include a light source, a wavelength selection device such as a monochromator or filter, a sample chamber, a light detector, and a readout device, usually also include a computer, which is used for storage and analysis of the spectra. The most useful machines scan the wavelength of the light that is incident on the sample and produce, as output, spectra of absorbance versus wavelength, such as those shown in textbook Figure 7.7.
The use of action spectra has been central to the development of our current understanding of photosynthesis. An action spectrum is a graph of the magnitude of the biological effect observed as a function of wavelength. Examples of effects measured by action spectra are oxygen evolution (Web Figure 7.1.C) and hormonal growth responses due to the action of phytochrome (see Chapter 17 of the textbook). Often an action spectrum can identify the chromophore responsible for a particular light-induced phenomenon. Action spectra were instrumental in the discovery of the existence of the two photosystems in O2-evolving photosynthetic organisms.
Some of the first action spectra were measured by T. W. Engelmann in the late 1800s (Web Figure 7.1.D). Engelmann used a prism to disperse sunlight into a rainbow that was allowed to fall on an aquatic algal filament. A population of O2-seeking bacteria was introduced into the system. The bacteria congregated in the regions of the filaments that evolved the most O2. These were the regions illuminated by blue light and red light, which are strongly absorbed by chlorophyll. Today, action spectra can be measured in room-sized spectrographs in which the scientist enters a huge monochromator and places samples for irradiation in a large area of the room bathed by monochromatic light. But the principle of the experiment is the same as that of Engelmann’s experiments.
An important technique in studies of photosynthesis is light-induced difference spectroscopy, which measures changes in absorbance (Web Figure 7.1.E). In this technique, bright light, often called actinic light, is used to illuminate a sample, while a dim beam of light is used to measure the absorbance of the sample at wavelengths other than that of the actinic beam. In this way a difference spectrum is obtained, which represents the changes in the absorption spectrum of the sample induced by illumination with the actinic light. Absorption bands that disappear upon illumination appear as negative peaks; new bands that appear upon illumination appear as positive peaks. Difference spectra give important clues to the identity of molecular species participating in the photoreactions of photosynthesis. The difference spectrum of the photooxidation of P700 (a chlorophyll that absorbs light of wavelength 700 nm